Toxin expression and function by an estuarine model species in a dynamic seasonal community

动态季节性群落中河口模型物种的毒素表达和功能

• 批准号: 1536530
• 负责人: Adam Reitzel
• 金额: $ 49.9万
• 依托单位: University of North Carolina at Charlotte
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536530&HistoricalAwards=false
• 关键词: Toxin; expression; function; estuarine; model

Venomous animals such as cnidarians, scorpions, and snakes utilize their toxins for a diversity of functions including defense from predators and for capturing prey. Thus, venom plays a pivotal and central role in the ecology of the animal producing it. There are several major hypotheses regarding the ecological factors that shape the diversity and expression of these molecules. A central hypothesis is that these toxins evolve rapidly due to their involvement in an evolutionary "arms race" between the organism and its potential predators and prey. Moreover, toxins are energetically expensive to produce so it is also hypothesized that their production is tightly regulated ("venom optimization hypothesis"), where individuals can module the amount and composition of their venom dependent on changes in diet and shifts in environmental factors such as temperature. Currently, there is a paucity of data to discern between these hypotheses. This research will provide an integrative approach to identify mechanisms that determine shifts in the quantity and composition of the venom essential for the feeding ecology of a model cnidarian specializing in estuarine habitats that are vulnerable to the ongoing climate change. This project will provide a synergistic international collaboration with Dr. Yehu Moran (The Hebrew University of Jerusalem, Israel) to connect environmental variation with the expression and potency of venom proteins. This research will provide mentoring and training for a postdoctoral fellow, graduate and undergraduate students at the University of North Carolina at Charlotte, and undergraduate students at Mitchell Community College in Statesville, NC. Additional research and educational opportunities will be provided for underrepresented students using PRODUCE, funded by the NSF through the NC Louis Stokes Alliance for Minority Participation to recruit, retain, and graduate students in STEM education. The PI will continue to involve high-school students in research through individual training, UNC Charlotte's outreach programs and the Burroughs Wellcome Science Enrichment program with the Olympic High School Biotechnology School.Knowledge of the environmental, genetic, and molecular factors involved in modulating expression of toxin proteins is essential to understand and predict how venomous species will respond to changes in the composition of biological communities. The research team will rigorously test hypotheses in the expression of toxin peptides by studying the starlet sea anemone, Nematostella vectensis, a predator of ecological importance that lives in estuaries along the eastern coast of North America. N. vectensis has emerged as a model cnidarian for ecological genomics due to the availability of a genome, its central position in estuarine food webs, and the ease of field collection and laboratory manipulation; a combination rarely available for venomous animals. Expression of venom genes in field collected anemones will be correlated with ingested prey identified using microscopy and DNA barcodes. This analysis will be compared in three different seasons to identify impacts of seasonal changes in abiotic variables as well as prey availability. Differences in expression of these toxin genes in the field could be related to tuning of the toxin composition to the prey available, presence of predators, and/or the physiological condition of the individual determined by degree of abiotic stress. The research team will differentiate between these potential causal factors through controlled laboratory experiments where anemones are exposed to two common stressors (temperature, UV), individual prey items, and a predator. In order to better understand the selectivity of these toxins to particular prey, behavioral and in vitro assays test toxicity of each genetic variant will be compared when exposed to distinct animal prey groups to determine the relative potency. Finally, sequence analyses will be used to investigate the molecular targets of the toxins in the prey animals to determine if these targets are potentially adapted to toxin alleles restricted to different geographic locations. These data will help determine a potential causative link between toxin evolution of a venomous animal and its prey and whether toxins and their targets are involved in an "arms race". This project is expected to have a significant impact on the understanding of the evolution of toxins in the context of ecological interactions in natural environments and contribute to our knowledge about toxin pharmacology for future design of novel insecticides.

诸如Cnidarians，Scorpions和Snakes之类的有毒动物利用其毒素来获得多种功能，包括捕食者的防御和捕获猎物。 因此，毒液在产生动物的动物的生态学中起关键和核心作用。关于塑造这些分子多样性和表达的生态因素，有几个主要假设。 一个核心假设是，这些毒素由于它们参与了有机体与其潜在捕食者和猎物之间进化的“军备竞赛”的参与而迅速进化。此外，毒素的生产在能量上很昂贵，因此也可以假设其产量受到严格调节（“毒液优化假设”），在这种情况下，个人可以将其毒液的数量和组成取决于饮食的变化以及温度诸如温度等环境因素的变化。 当前，这些假设之间存在很少的数据。这项研究将提供一种综合方法来识别确定毒液数量和组成的机制，对于毒液的喂养生态学的量和组成，专门从事河口栖息地的饲料生态学，这些植物容易受到持续的气候变化的影响。该项目将与耶胡·莫兰（Yehu Moran）博士（以色列希伯来大学）提供协同的国际合作，以将环境变化与毒素的表达和效力联系起来。这项研究将为北卡罗来纳大学夏洛特大学的博士后研究员，研究生和本科生提供指导和培训，以及北卡罗来纳州Statesville Mitchell社区学院的本科生。将提供其他研究和教育机会，以提供代表性不足的学生使用农产品，由NSF通过NC Louis Stokes Alliance资助，以招募，保留和研究生在STEM教育中。 PI将继续通过个人培训，夏洛特UNC的外展计划和Burroughs Wellcome科学丰富计划与奥林匹克高中的生物技术学校进行研究。对环境，遗传和分子因素的了解，涉及毒素蛋白表达对毒素蛋白的表达至关重要，可以预测毒素的依从性，对毒素的表达至关重要。 研究小组将通过研究恒星海葵，nematostella vectensis，对毒素肽的表达进行严格检验，这是一种生态重要性的捕食者，居住在北美东海岸的河口中。 由于基因组的可用性，其在河口食品网中的中心位置以及易于田间收集和实验室操作，因此已成为生态基因组学模型的模型；一个很少用于有毒动物的组合。 毒液在收集的海葵中的毒液基因的表达将与使用显微镜和DNA条形码鉴定的摄入的猎物相关。 该分析将在三个不同的季节中进行比较，以确定非生物变量的季节变化以及猎物可用性的影响。 这些毒素基因表达在现场的表达差异可能与将毒素组成对猎物的可用捕食，捕食者的存在和/或个体的生理状况的调整有关。 研究团队将通过受控实验室实验区分这些潜在的因果因素，在这些实验室实验中，它们会暴露于两个常见的压力源（温度，紫外线），单个猎物项目和一个捕食者。为了更好地了解这些毒素对特定猎物的选择性，将在暴露于不同动物猎物基团时比较每个遗传变异的毒性，以确定相对效力。 最后，将使用序列分析来研究猎物中毒素的分子靶标，以确定这些靶标是否可能适应了仅限于不同地理位置的毒素等位基因。这些数据将有助于确定有毒动物的毒素进化与其猎物的毒素进化与毒素及其靶标之间的潜在因果关系。 在自然环境中生态相互作用的背景下，该项目有望对对毒素进化的理解产生重大影响，并有助于我们对毒素药理学的了解，以实现新型杀虫剂的未来设计。